zh_trans: add automated-tasks-with-cron-jobs.md

zh_trans: add job/automated-tasks-with-cron-jobs.md
2018-11-18 23:55:45 +08:00 · 2018-11-18 23:55:45 +08:00 · 608cad5a33
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+<!--
+---
+title: Running Automated Tasks with a CronJob
+reviewers:
+- chenopis
+content_template: templates/task
+weight: 10
+---
+-->
+
+---
+reviewers:
+- chenopis
+
+title: 使用 CronJob 运行自动化任务
+content_template: templates/task
+weight: 10
+---
+
+{{% capture overview %}}
+
+<!--
+You can use [CronJobs](/docs/concepts/workloads/controllers/cron-jobs) to run jobs on a time-based schedule.
+These automated jobs run like [Cron](https://en.wikipedia.org/wiki/Cron) tasks on a Linux or UNIX system.
+
+Cron jobs are useful for creating periodic and recurring tasks, like running backups or sending emails.
+Cron jobs can also schedule individual tasks for a specific time, such as if you want to schedule a job for a low activity period.
+-->
+
+你可以利用 [CronJobs](/docs/concepts/workloads/controllers/cron-jobs) 执行基于时间调度的任务。这些自动化任务和 Linux 或者 Unix 系统的 [Cron](https://en.wikipedia.org/wiki/Cron) 任务类似。
+
+CronJobs 在创建周期性以及重复性的任务时很有帮助，例如执行备份操作或者发送邮件。CronJobs也可以在特定时间调度单个任务，例如你想调度低活跃周期的任务。
+
+{{< note >}}
+<!--
+CronJob resource in `batch/v2alpha1` API group has been deprecated starting from cluster version 1.8.
+You should switch to using `batch/v1beta1`, instead, which is enabled by default in the API server.
+Examples in this document use `batch/v1beta1` in all examples.
+-->
+在`batch/v2alpha1` API 组中， CronJob 资源从集群版本1.8开始已经被去掉了。你应该切换到`batch/v1beta1`，在这里的API 服务器中是默认开启的。本文中的所有示例使用了`batch/v1beta1`。
+{{< /note >}}
+
+<!--
+Cron jobs have limitations and idiosyncrasies.
+For example, in certain circumstances, a single cron job can create multiple jobs.
+Therefore, jobs should be idempotent.
+For more limitations, see [CronJobs](/docs/concepts/workloads/controllers/cron-jobs).
+-->
+
+CronJobs有一些限制和特点。
+例如，在特定状况下，一个单独的cron job可以创建多个任务。
+因此，任务应该是幂等的。
+查看更多限制，请参考[CronJobs](/docs/concepts/workloads/controllers/cron-jobs).
+
+{{% /capture %}}
+
+{{% capture prerequisites %}}
+
+* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
+<!--
+* You need a working Kubernetes cluster at version >= 1.8 (for CronJob). For previous versions of cluster (< 1.8)
+you need to explicitly enable `batch/v2alpha1` API by passing `--runtime-config=batch/v2alpha1=true` to
+the API server (see [Turn on or off an API version for your cluster](/docs/admin/cluster-management/#turn-on-or-off-an-api-version-for-your-cluster)
+for more), and then restart both the API server and the controller manager
+component.
+-->
+
+* 你需要一个版本 >=1.8 且工作正常的 Kubernetes 集群。对于更早的版本（ <1.8 ），你需要对API 服务器设置 `--runtime-config=batch/v2alpha1=true` 来开启 `batch/v2alpha1` API，(更多信息请查看 [为你的集群开启或关闭 API 版本](/docs/admin/cluster-management/#turn-on-or-off-an-api-version-for-your-cluster)
+), 然后重启 API 服务器和控制管理器。
+
+{{% /capture %}}
+
+{{% capture steps %}}
+
+<!--
+## Creating a Cron Job
+
+Cron jobs require a config file.
+This example cron job config `.spec` file prints the current time and a hello message every minute:
+-->
+
+## 创建 CronJob
+
+Cron Job需要一个配置文件。
+本例中 Cron Job 的`.spec` 配置文件每分钟打印出当前时间和一个问好信息：
+
+{{< codenew file="application/job/cronjob.yaml" >}}
+
+<!--
+Run the example cron job by downloading the example file and then running this command:
+-->
+
+想要运行示例的 CronJob，可以下载示例文件并执行命令：
+
+```shell
+$ kubectl create -f ./cronjob.yaml
+cronjob "hello" created
+```
+
+<!--
+Alternatively, you can use `kubectl run` to create a cron job without writing a full config:
+-->
+
+或者你也可以使用 `kubectl run` 来创建一个 CronJob 而不需要编写完整的配置：
+
+```shell
+$ kubectl run hello --schedule="*/1 * * * *" --restart=OnFailure --image=busybox -- /bin/sh -c "date; echo Hello from the Kubernetes cluster"
+cronjob "hello" created
+```
+
+<!--
+After creating the cron job, get its status using this command:
+-->
+
+创建好CronJob后，使用下面的命令来获取其状态：
+
+```shell
+$ kubectl get cronjob hello
+NAME      SCHEDULE      SUSPEND   ACTIVE    LAST-SCHEDULE
+hello     */1 * * * *   False     0         <none>
+```
+
+<!--
+As you can see from the results of the command, the cron job has not scheduled or run any jobs yet.
+Watch for the job to be created in around one minute:
+-->
+
+就像你从命令返回结果看到的那样，CronJob还没有调度或执行任何任务。大约需要一分钟任务才能创建好。
+
+```shell
+$ kubectl get jobs --watch
+NAME               DESIRED   SUCCESSFUL   AGE
+hello-4111706356   1         1         2s
+```
+
+<!--
+Now you've seen one running job scheduled by the "hello" cron job.
+You can stop watching the job and view the cron job again to see that it scheduled the job:
+-->
+
+现在你已经看到了一个运行中的任务被 “hello” CronJob调度。你可以停止监视这个任务，然后再次查看CronJob就能看到它调度任务：
+
+```shell
+$ kubectl get cronjob hello
+NAME      SCHEDULE      SUSPEND   ACTIVE    LAST-SCHEDULE
+hello     */1 * * * *   False     0         Mon, 29 Aug 2016 14:34:00 -0700
+```
+
+<!--
+You should see that the cron job "hello" successfully scheduled a job at the time specified in `LAST-SCHEDULE`.
+There are currently 0 active jobs, meaning that the job has completed or failed.
+
+Now, find the pods that the last scheduled job created and view the standard output of one of the pods.
+Note that the job name and pod name are different.
+-->
+
+你应该能看到 “hello” CronJob 在 `LAST-SCHEDULE` 声明的时间点成功的调度了一次任务。有0个活跃的任务意味着任务执行完毕或这执行失败。
+
+现在，找到最后一次调度任务创建的 Pod 并查看一个 Pod 的标准输出。请注意任务名称和 Pod 名称是不同的。
+
+
+```shell
+# Replace "hello-4111706356" with the job name in your system
+$ pods=$(kubectl get pods --selector=job-name=hello-4111706356 --output=jsonpath={.items..metadata.name})
+
+$ echo $pods
+hello-4111706356-o9qcm
+
+$ kubectl logs $pods
+Mon Aug 29 21:34:09 UTC 2016
+Hello from the Kubernetes cluster
+```
+
+<!--
+## Deleting a Cron Job
+
+When you don't need a cron job any more, delete it with `kubectl delete cronjob`:
+-->
+
+## 删除 CronJob
+
+当你不再需要CronJob时，可以用 `kubectl delete cronjob` 删掉它：
+
+```shell
+$ kubectl delete cronjob hello
+cronjob "hello" deleted
+```
+<!--
+Deleting the cron job removes all the jobs and pods it created and stops it from creating additional jobs.
+You can read more about removing jobs in [garbage collection](/docs/concepts/workloads/controllers/garbage-collection/).
+-->
+
+删除 CronJob 会清除它创建的所有任务和 Pod，并阻止它创建额外的任务。你可以查阅删除任务的更多信息 [垃圾收集](/docs/concepts/workloads/controllers/garbage-collection/)。
+
+<!--
+## Writing a Cron Job Spec
+
+As with all other Kubernetes configs, a cron job needs `apiVersion`, `kind`, and `metadata` fields. For general
+information about working with config files, see [deploying applications](/docs/user-guide/deploying-applications),
+and [using kubectl to manage resources](/docs/user-guide/working-with-resources) documents.
+
+A cron job config also needs a [`.spec` section](https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status).
+-->
+
+## 编写CronJob声明信息
+
+像 Kubernetes 的其他配置一样，CronJob需要 `apiVersion`, `kind`, and `metadata` 域。配置文件的一般信息，请参考 [部署应用](/docs/user-guide/deploying-applications) 和 [使用kubectl管理资源](/docs/user-guide/working-with-resources).
+
+CronJob 配置也需要包括[`.spec`](https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status).
+
+{{< note >}} 
+<!--
+All modifications to a cron job, especially its `.spec`, are applied only to the following runs. 
+-->
+对CronJob的所有改动，特别是它的 `.spec`，只有在下面的执行中应用。
+{{< /note >}}
+
+<!--
+### Schedule
+
+The `.spec.schedule` is a required field of the `.spec`.
+It takes a [Cron](https://en.wikipedia.org/wiki/Cron) format string, such as `0 * * * *` or `@hourly`, as schedule time of its jobs to be created and executed.
+-->
+
+### 调度
+
+`.spec.schedule` 是 `.spec` 需要的域。它使用了 [Cron](https://en.wikipedia.org/wiki/Cron) 格式串，例如 `0 * * * *` or `@hourly` ，做为它的任务被创建和执行的调度时间。
+
+<!--
+The format also includes extended `vixie cron` step values. As explained in the [FreeBSD manual](https://www.freebsd.org/cgi/man.cgi?crontab%285%29):
+-->
+
+该格式也包含了扩展的 `vixie cron` 步长值。[FreeBSD 手册](https://www.freebsd.org/cgi/man.cgi?crontab%285%29)中解释如下:
+
+<!--
+> Step values can be	used in	conjunction with ranges.  Following a range
+> with ``/<number>''	specifies skips	of the number's	value through the
+> range.  For example, ``0-23/2'' can be used in the	hours field to specify
+> command execution every other hour	(the alternative in the	V7 standard is
+> ``0,2,4,6,8,10,12,14,16,18,20,22'').  Steps are also permitted after an
+> asterisk, so if you want to say ``every two hours'', just use ``*/2''.
+-->
+
+> 步长可被用于范围组合。范围后面带有 ``/<数字>'' 可以声明范围内的步幅数值。
+> 例如，``0-23/2'' 可被用在小时域来声明命令在其他数值的小时数执行（ V7 标准中对应的方法是``0,2,4,6,8,10,12,14,16,18,20,22''）。
+> 步长也可以放在通配符后面，因此如果你想表达 ``每两小时''，就用 ``*/2'' 。
+
+{{< note >}}
+<!--
+A question mark (`?`) in the schedule has the same meaning as an asterisk `*`, that is, it stands for any of available value for a given field.
+-->
+调度中的问号 (`?`) 和星号  `*` 含义相同，表示给定域的任何可用值。
+{{< /note >}}
+
+<!--
+### Job Template
+
+The `.spec.jobTemplate` is the template for the job, and it is required.
+It has exactly the same schema as a [Job](/docs/concepts/workloads/controllers/jobs-run-to-completion/), except that it is nested and does not have an `apiVersion` or `kind`.
+For information about writing a job `.spec`, see [Writing a Job Spec](/docs/concepts/workloads/controllers/jobs-run-to-completion/#writing-a-job-spec).
+-->
+
+### 任务模版
+
+`.spec.jobTemplate`是任务的模版，它是必须的。它和 [Job](/docs/concepts/workloads/controllers/jobs-run-to-completion/)的语法完全一样，除了它是嵌套的没有 `apiVersion` 和 `kind`。
+编写任务的 `.spec` ，请参考 [编写任务的Spec](/docs/concepts/workloads/controllers/jobs-run-to-completion/#writing-a-job-spec)。
+
+<!--
+### Starting Deadline
+
+The `.spec.startingDeadlineSeconds` field is optional.
+It stands for the deadline in seconds for starting the job if it misses its scheduled time for any reason.
+After the deadline, the cron job does not start the job.
+Jobs that do not meet their deadline in this way count as failed jobs.
+If this field is not specified, the jobs have no deadline.
+-->
+
+### 开始的最后期限
+
+`.spec.startingDeadlineSeconds` 域是可选的。
+它表示任务如果由于某种原因错过了调度时间，开始该任务的截止时间的秒数。过了截止时间，CronJob就不会开始任务。
+不满足这种最后期限的任务会被统计为失败任务。如果该域没有声明，那任务就没有最后期限。
+
+<!--
+The CronJob controller counts how many missed schedules happen for a cron job. If there are more than 100 missed
+schedules, the cron job is no longer scheduled. When `.spec.startingDeadlineSeconds` is not set, the CronJob
+controller counts missed schedules from `status.lastScheduleTime` until now. For example, one cron job is
+supposed to run every minute, the `status.lastScheduleTime` of the cronjob is 5:00am, but now it's 7:00am.
+That means 120 schedules were missed, so the cron job is no longer scheduled. If the `.spec.startingDeadlineSeconds`
+field is set (not null), the CronJob controller counts how many missed jobs occurred from the value of
+`.spec.startingDeadlineSeconds` until now. For example, if it is set to `200`, it counts how many missed
+schedules occurred in the last 200 seconds. In that case, if there were more than 100 missed schedules in the
+last 200 seconds, the cron job is no longer scheduled. 
+-->
+
+CronJob 控制器会统计错过了多少次调度。如果错过了100次以上的调度，CronJob就不再调度了。当没有设置 `.spec.startingDeadlineSeconds` 时，CronJob控制器统计从`status.lastScheduleTime`到当前的调度错过次数。
+例如一个CronJob期望每分钟执行一次，`status.lastScheduleTime`是 5:00am，但现在是 7:00am。那意味着120次调度被错过了，所以 CronJob将不再被调度。
+如果设置了 `.spec.startingDeadlineSeconds` 域(非空)，CronJob 控制器统计从 `.spec.startingDeadlineSeconds` 到当前时间错过了多少次任务。
+例如设置了 `200`，它会统计过去200秒内错过了多少次调度。在那种情况下，如果过去200秒内错过了超过100次的调度，CronJob就不再调度。
+
+<!--
+### Concurrency Policy
+
+The `.spec.concurrencyPolicy` field is also optional.
+It specifies how to treat concurrent executions of a job that is created by this cron job.
+the spec may specify only one of the following concurrency policies:
+
+* `Allow` (default): The cron job allows concurrently running jobs
+* `Forbid`: The cron job does not allow concurrent runs; if it is time for a new job run and the previous job run hasn't finished yet, the cron job skips the new job run
+* `Replace`: If it is time for a new job run and the previous job run hasn't finished yet, the cron job replaces the currently running job run with a new job run
+
+Note that concurrency policy only applies to the jobs created by the same cron job.
+If there are multiple cron jobs, their respective jobs are always allowed to run concurrently.
+-->
+
+### 重叠规则
+
+`.spec.concurrencyPolicy` 也是可选的。它声明了CronJob创建的任务重叠发生时如何处理。spec 仅能声明下列规则中的一种：
+
+* `Allow` (默认)：CronJob允许重叠执行任务。
+* `Forbid`： CronJob不允许重叠执行任务；如果新任务的执行时间到了而老任务没有执行完，CronJob会忽略新任务的执行。
+* `Replace`：如果新任务的执行时间到了而老任务没有执行完，CronJob会用新任务替换当前正在运行的任务。
+
+请注意，重叠规则仅适用于相同CronJob创建的任务。如果有多个CronJob，它们相应的任务总是允许重叠执行的。
+
+<!--
+### Suspend
+
+The `.spec.suspend` field is also optional.
+If it is set to `true`, all subsequent executions are suspended.
+This setting does not apply to already started executions.
+Defaults to false.
+-->
+
+### 挂起
+
+`.spec.suspend`域也是可选的。如果设置为 `true` ，后续发生的执行都会挂起。这个设置对已经开始的执行不起作用。默认是关闭的。
+
+{{< caution >}}
+<!--
+Executions that are suspended during their scheduled time count as missed jobs.
+When `.spec.suspend` changes from `true` to `false` on an existing cron job without a [starting deadline](#starting-deadline), the missed jobs are scheduled immediately.
+-->
+在调度时间内挂起的执行都会被统计为错过的任务。当 `.spec.suspend` 从 `true` 改为 `false` 时，且没有 [开始的最后期限](#starting-deadline)，错过的任务会被立即调度。
+{{< /caution >}}
+
+<!--
+### Jobs History Limits
+
+The `.spec.successfulJobsHistoryLimit` and `.spec.failedJobsHistoryLimit` fields are optional.
+These fields specify how many completed and failed jobs should be kept.
+By default, they are set to 3 and 1 respectively.  Setting a limit to `0` corresponds to keeping none of the corresponding kind of jobs after they finish.
+-->
+
+### 任务历史限制
+
+`.spec.successfulJobsHistoryLimit` 和 `.spec.failedJobsHistoryLimit`是可选的。
+这两个域声明了有多少执行完成和失败的任务会被保留。
+默认设置为3和1。限制设置为0代表相应类型的任务完成后不会保留。
+
+{{% /capture %}}